1. Field of the Invention
This invention relates to polyamide adhesives for bonding fabrics which allow for a lower bonding temperature than had been possible with similar previously available polyamide fabric bonding resins. The polyamide adhesives of the present invention are particularly suitable for use as fusible interliners for fabrics which demonstrate excellent retention of adhesive properties even after repeated cleaning by laundering and/or dry cleaning. The polyamide adhesive is an amidification product of
(a) a caprolactam polymer, PA1 (b) a diamine component which is 50-75 eq. % hexamethylene diamine, and 25-50 eq. % piperazine, or 2-methyl pentamethylene diamine, and PA1 (c) a mixture of a polymeric fat acid and an aliphatic straight chain co-dicarboxylic acid having 6-12 carbon atoms. PA1 (a) PA1 (b) at least one aliphatic straight chain co-dicarboxylic acid, PA1 (c) an aliphatic straight-chain diprimary diamine and PA1 (d) caprolactam. PA1 (a) caprolactam, amino-caproic acid or mixtures PA1 (b) a diamine component which is PA1 (c) a mixture of polymeric fat acid and an aliphatic straight chain co-dicarboxylic acid having 6-12 carbon atoms. PA1 (a) caprolactam, amino-caproic acid or mixtures thereof, PA1 (b) a diamine component which is 50-75% hexamethylene diamine and 25-50% piperazine, or 2-methyl pentamethylene diamine, and PA1 (c) a mixture of a polymeric fat acid and an aliphatic straight chain co-dicarboxylic acid having 6-12 carbon atoms.
2. Statement of the Related Art
Many attempts to use various polymers in fabric bonding have been found deficient in one or more regards, such as insufficient bonding, little resistance to dry cleaning or laundering, unacceptably high temperature required for fabric bonding, and hand feel (too inflexible to provide desirable drape and softness when used in garment or drapery manufacture). Recently, U.S. Pat. No. 4,217,256 attempted to provide a satisfactory hot melt adhesive for bonding fusible interliners with fabrics. The polyamide adhesives therein disclosed are polymeric fat acid terpolyamides having a melt index at 175.degree. C. of at least 30 and a melt viscosity of not more than 125 poise at 220.degree. C. wherein the properties are controlled within certain ranges. Those terpolyamides are thermal amidification products prepared at 100.degree.-300.degree. C. for a time sufficient to affect amidification of a caprolactam polymer, the polyamide of hexamethylene diamine and a polymeric fat acid and the polyamide of hexamethylene diamine and a co-dicarboxylic acid having 10-12 carbon atoms. Although the resins described in U.S. Pat. No. 4,217,256 are found to be useful in a variety of applications, there are certain heat sensitive synthetic fabrics which require substantially lower fusion points than can be achieved with these previously available resins.
U.S. Pat. No. 4,045,389 attempted to provide a satisfactory melt adhesive to overcome the deficiency in cleanability of textiles bonded with polyamide adhesive having certain melt viscosities within a relatively narrow range of 25-600 Pas measured at 200.degree. C. obtained by using certain amounts of monocarboxylic acids as viscosity regulators. These polyamides were reaction products of caprolactam, various diamines and a mixture of dimerized fatty acids and other co-dicarboxylic acids. With the use of these polyamide adhesives, it is not possible to achieve the lowered fusion points possible with the adhesives of the present invention.
U.S. Pat. No. 4,396,759 discloses polyamide fabric bonding resins having a melt viscosity, measured at 220.degree. C. of 5-150 Pas. and being the reaction product of approximately equivalent amounts of an acid component and a basic component, the acid component comprising
(1) a dimerized fatty acid, and optionally PA2 (2) a monocarboxylic acid; PA2 (1) 50-75 eq. % hexamethylene diamine, PA2 (2) 25-50 eq. % piperazine, or 2-methyl pentamethylene diamine,
said basic component comprising
These products are said to evidence very good initial resistance to tear, very high wet strengths, and outstanding values of tear resistance after repeated laundering cycles. These polyamide resins, however, do not evidence the lowered fusion points which have been achieved with the polyamide fabric bonding resins of the present invention.
U.S. Pat. No. 4,150,002 is concerned with polyamides and polyesteramides having melt viscosities from 25 to 600 Pas. at 220.degree. C., which are useful as melt adhesives for textiles. These materials are condensation products formed between (a) a dimerized fatty acid component containing at least 70% of dimeric acid; and (b) a 6-13 carbon atoms aliphatic straight chain co-dicarboxylic acid; (c) a 6-12 carbon atoms aliphatic straight-chain diprimary diamine; and (d) caprolactam and/or -amino-caproic acid; the polyesteramides additionally containing a further component (e) which is caprolactone and/or -hydroxycaproic acid. However, these hot melt fabric adhesives similarly lack the lowered fusion points achievable with polyamide fabric bonding resins of the present invention.